Add orzo to boiling water and cook for 9 minutes. Drain the orzo, saving the cooking water. Add 2 cups hot cooking water to bulgur (add additional boiling water to make 2 cups as needed). Let the bulgur set for 45 minutes. In large bowl, combine the orzo, celery, carrots, cucumber, cranberries, broccoli, onion, and bulgur. Whisk together the oil, vinegar, sugar, and dry mustard. Pour over the bulgur mixture. Cover and chill. Top with feta cheese before serving. Serves 8 (1/2 cup serving).